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Comment: Re:Science Writers: Stop Causing Us Intellectual P (Score 1) 147

by Zorpheus (#47150125) Attached to: Strange New World Discovered: The "Mega Earth"
Funny that we have exactly the same in German. The conclusion from the logical meaning is 3.3, but no one uses it this way. People who value the logical meaning say 2.3 times as large, they just would not use it, and the others use it the way that it is commonly used, although it is illogical.

Comment: Re:Simple (Score 1) 250

by Zorpheus (#47063895) Attached to: As NASA Seeks Next Mission, Russia Holds the Trump Card
What I meant is: if the USA would start capturing Chinese spying satellites China would probably retaliate by destroying one or more American satellites. Currently the USA has an advantage due to a higher number and quality of satellites in orbit, if it starts to attack satellites it will lose this advantage due to the counterreactions.
The Chinese method is simple and produces lots of debris in orbit. If this is done a few times orbits will become unusable because the danger of collisions becomes too high. The USA can not use this method since it will block itself with it, but for China it is ok, especially as a counter-threat.

Comment: Re:Spoiler at the end. Answer is "No" (Score 4, Informative) 135

by Zorpheus (#46912115) Attached to: Is There a Limit To a Laser's Energy?
I just searched for an answer to this question. Seems that pair generation by irradiation of matter (e.g. a mirror) is shown experimentally and can reach quite high intensities:
http://journals.aps.org/prl/ab...
Generation in vacuum though seems to be shown only in models until now:
http://iopscience.iop.org/0295...
http://journals.aps.org/pra/ab...
Seems that the reaction rate is much lower, so maybe this is not a limiting factor for building a laser.
Normally high intensities are achieved by building a pulsed laser. This produces a beam of laser pulses, which is then focussed into a tiny spot. Intensities in this spot can be alot higher than inside the laser cavity. You could achieve higher laser intensities just by building a larger laser (like http://en.wikipedia.org/wiki/N... ).
Inside the laser cavity intensities are normally limited by the effects of nonlinear optics ( http://en.wikipedia.org/wiki/N... ), which occur in all kinds of matter.

Comment: Re:Sorry but (Score 1) 179

Hmm, to me the principle of holding a plasma in place by a magnetic field is sound. You can not block electromagnetic waves with any magnetic or electric fields, though the plasma absorbs all kinds of electromagnetic radiation.
Though both the high magnetic field strengths necessary and the energy loss due to thermal radiation probably make this impractical or impossible to build.

Comment: Re:How low can you go?(power density) (Score 2) 152

What bollocks. I think the actual question to ask is how it's possible to create the conditions for an very large (the size of the mine)and extremely low density (the concentration of natural ore) nuclear reactor.

In the days the preference for civilian reactors was to develop further along the design of the compact high density submarine reactors. The nuclear industry never got over that. There are prototypes of large reactors with much lower power density. It's a natural question to ask how low enrichment and low density one can go.

2 billion years ago the concentration of U-235 was still 3% of the uranium. It decreased due to the shorter half-lifes of U-235.
A pressurized heave water reactor runs with today's unenriched uranium, so we are better than that already.

Comment: Re:Flight recorder (Score 1) 491

by Zorpheus (#46565749) Attached to: How Satellite Company Inmarsat Tracked Down MH370
The Indian ocean is very deep, it is a remote location and two weeks have passed already. This black box will be harder to find than that of the Air France flight which got lost over the Atlantic. Back then they said that the sender of the black box will run for a month. I don't believe that they will find it this time.

Mathemeticians stand on each other's shoulders while computer scientists stand on each other's toes. -- Richard Hamming

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